Mapbox RMTileCacheBackgroundDelegate回调不起作用

Question

下面有快速密码。地图上的一切都如预期的那样工作，但我从未看到任何RMTileCashBackgroundDelegate方法正在被调用。我看到的就是“缓存开始了！”然后什么都没有。我试过很多次调整，但都没能成功。任何帮助都将不胜感激！

class MapboxViewController: UIViewController, RMMapViewDelegate, RMTileCacheBackgroundDelegate {
    var mapView: RMMapView!

    override func viewDidLoad() {
        super.viewDidLoad()

        let mapSource:RMMapboxSource = RMMapboxSource(mapID: "myMapId")

        mapView = RMMapView(frame: self.view.bounds, andTilesource: mapSource)
        mapView.delegate = self

        //background caching
        mapView.tileCache.backgroundCacheDelegate = self
        mapView.tileCache.beginBackgroundCacheForTileSource(mapView.tileSource, southWest: swBounds, northEast: neBounds, minZoom: 13, maxZoom: 17)
    }

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)

        mainView.addSubview(mapView)
    }

    func tileCache(tileCache: RMTileCache!, didBeginBackgroundCacheWithCount tileCount: Int, forTileSource tileSource: RMTileSource) {
        println("Caching started!")
    }
    func tileCache(tileCache: RMTileCache!, didBackgroundCacheTile tile: RMTile, withIndex tileIndex: Int, ofTotalTileCount totalTileCount: Int) {
        println("Cached tile \(tileIndex) of \(totalTileCount)")
    }
    func tileCache(tileCache: RMTileCache!, didReceiveError error: NSError!, whenCachingTile tile: RMTile) {
        println("Error caching tile")
    }
    func tileCacheDidCancelBackgroundCache(tileCache: RMTileCache!) {
        println("Caching cancelled!")
    }
    func tileCacheDidFinishBackgroundCache(tileCache: RMTileCache!) {
        println("Caching complete!")
    }
}

Answer 1

这里有两个问题，其中一个问题在上面的代码中并不明显：

1. tileCache函数采用的是UInt而不是Int (升级到SWIFT1.2后强制使用)
2. 我在beginBackgroundCacheForTileSource中的边框是四舍五入的，所以我最终得到了一条没有瓷砖的边线。这对我来说太草率了，实际上导致Mapbox iOS SDK崩溃。

感谢Mapbox支持他们的帮助。下面是Swift中一个很好的离线缓存示例，以供参考：https://github.com/mapbox/mapbox-ios-sdk-offline